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Christopher Gomez, Christopher
Department of Geography, University of Canterbury

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Conceptual Reflections on Ethics for International Research Collaborations in Disaster Impacted Areas from the Experiences in Indonesia, New Zealand and Japan Gomez, Christopher
Forum Geografi Vol 28, No 2 (2014)
Publisher : Forum Geografi

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Abstract

The present contribution is by no means a first attempt at considering the ethics in human activities, interactions in disaster impacted areas, but it is more the case of looking at international research that present a very particular difficulty for ethics: the notion of trans-boundary, multi-dimensional idea of one group not really belonging within another, but which will perform functions inside this second group and eventually alter, modify some of the original organs. This paper explain the reflections of the ethical consideration of international research collaboration in disaster impacted areas which are emerged from the experiences in Indonesia, New Zealand and Japan.
Geospatial Assessment of Coseismic Landslides in Baturagung Area Saputra, Aditya; Sartohadi, Junun; Hadmoko, Danang Sri; Gomez, Christopher
Forum Geografi Vol 29, No 2 (2015): Forum Geografi
Publisher : Universitas Muhammadiyah Surakarta

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Abstract

Java, the most densely populated island in Indonesia, is located on top of the most seismically active areas in Southeast Asia: the Sunda Megathrust. This area is frequently hit by strong earthquake. More than 3,300 M>5earthquakesoccurred between 1973-2014. The wide range of mountainous areas and high intensity of rainfall, make several part of the island one of the most exposed regions for coseismic landslides such as Baturagung area, the Southeast mountainous area of Yogyakarta Province. An integrated method between RS and GIS was used to conduct the vulnerability assessment due to the lack of the site specific slope instability analysis and coseismic landslides data. The seismic zonation of Baturagung area was obtained based on the analysis of Kanai attenuation. The geologic information was extracted using remote sensing interpretation based on the 1:100,000 geologic map of Yogyakarta and geomorphologic map of Baturagung area as well. The coseismic landslide hazard assessment has been estimated using scoring analysis in the GIS platform proposed by Mora and Vahrson (1993) with several modification. The accomplished coseismic landslide hazard map shows medium hazard coverage in the eastern areas, in the upper slope of Baturagung area, which consists of Semilir Formation. The result provides a distinct description of coseismic landslides hazard distribution in Batuaragung area. However, it should only be the preliminary assessment of the site specific investigation especially on valuable area or asset. 
Photogrammetry-based Texture Analysis of a Volcaniclastic Outcrop-peel: Low-cost Alternative to TLS and Automation Potentialities using Haar Wavelet and Spatial-Analysis Algorithms Gomez, Christopher; Kataoka, Kyoko; Saputra, Aditya; Wassmer, Patrick; Urabe, Atsushi; Morgenroth, Justin; Kato, Akira
Forum Geografi Vol 31, No 1 (2017): July 2017
Publisher : Universitas Muhammadiyah Surakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.23917/forgeo.v31i1.3977

Abstract

Numerous progress has been made in the field of applied photogrammetry in the last decade, including the usage of close-range photogrammetry as a mean of conservation and record of outcrops. In the present contribution, we use the SfM-MVS method combined with a wavelet decomposition analysis of the surface, in order to relate it to morphological and surface roughness data. The results demonstrated that wavelet decomposition and RMS could provide a rapid insight on the location of coarser materials and individual outliers, while arithmetic surface roughness were more useful to detect units or layers that are similar on the outcrop. The method also emphasizes the fact that the automation of the process does not allows clear distinction between any artefact crack or surface change and that human supervision is still essential despite the original goal of automating the outcrop surface analysis.
Geospatial Assessment of Coseismic Landslides in Baturagung Area Saputra, Aditya; Sartohadi, Junun; Hadmoko, Danang Sri; Gomez, Christopher
Forum Geografi Vol 29, No 2 (2015): December 2015
Publisher : Universitas Muhammadiyah Surakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.23917/forgeo.v29i2.693

Abstract

Java, the most densely populated island in Indonesia, is located on top of the most seismically active areas in Southeast Asia: the Sunda Megathrust. This area is frequently hit by strong earthquake. More than 3,300 M>5earthquakesoccurred between 1973-2014. The wide range of mountainous areas and high intensity of rainfall, make several part of the island one of the most exposed regions for coseismic landslides such as Baturagung area, the Southeast mountainous area of Yogyakarta Province. An integrated method between RS and GIS was used to conduct the vulnerability assessment due to the lack of the site specific slope instability analysis and coseismic landslides data. The seismic zonation of Baturagung area was obtained based on the analysis of Kanai attenuation. The geologic information was extracted using remote sensing interpretation based on the 1:100,000 geologic map of Yogyakarta and geomorphologic map of Baturagung area as well. The coseismic landslide hazard assessment has been estimated using scoring analysis in the GIS platform proposed by Mora and Vahrson (1993) with several modification. The accomplished coseismic landslide hazard map shows medium hazard coverage in the eastern areas, in the upper slope of Baturagung area, which consists of Semilir Formation. The result provides a distinct description of coseismic landslides hazard distribution in Batuaragung area. However, it should only be the preliminary assessment of the site specific investigation especially on valuable area or asset. 
Conceptual Reflections on Ethics for International Research Collaborations in Disaster Impacted Areas from the Experiences in Indonesia, New Zealand and Japan Gomez, Christopher
Forum Geografi Vol 28, No 2 (2014): December 2014
Publisher : Universitas Muhammadiyah Surakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.23917/forgeo.v28i2.432

Abstract

The present contribution is by no means a first attempt at considering the ethics in human activities, interactions in disaster impacted areas, but it is more the case of looking at international research that present a very particular difficulty for ethics: the notion of trans-boundary, multi-dimensional idea of one group not really belonging within another, but which will perform functions inside this second group and eventually alter, modify some of the original organs. This paper explain the reflections of the ethical consideration of international research collaboration in disaster impacted areas which are emerged from the experiences in Indonesia, New Zealand and Japan.
Spatio-Temporal Distribution of Landslides in Java and the Triggering Factors Hadmoko, Danang Sri; Lavigne, Franck; Sartohadi, Junun; Gomez, Christopher; Daryono, D
Forum Geografi Vol 31, No 1 (2017): July 2017
Publisher : Universitas Muhammadiyah Surakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.23917/forgeo.v31i1.3790

Abstract

Java Island, the most populated island of Indonesia, is prone to landslide disasters. Their occurrence and impact have increased mainly as the result of natural factors, aggravated by human imprint. This paper is intended to analyse: (1) the spatio-temporal variation of landslides in Java during short term and long-term periods, and (2) their causative factors such as rainfall, topography, geology, earthquakes, and land-use. The evaluation spatially and temporally of historical landslides and consequences were based on the landslide database covering the period of 1981 – 2007 in the GIS environment. Database showed that landslides distributed unevenly between West Java (67 %), Central Java (29 %) and East Java (4 %). Slope failures were most abundant on the very intensively weathered zone of old volcanic materials on slope angles of 30O – 40O. Rainfall threshold analysis showed that shallow landslides and deep-seated landslides were triggered by rainfall events of 300 – 600 mm and > 600 mm respectively of antecedent rainfall during 30 consecutive days, and many cases showed that the landslides were not always initiated by intense rainfall during the landslide day. Human interference plays an important role in landslide occurrence through land conversion from natural forest to dryland agriculture which was the host of most of landslides in Java. These results and methods can be used as valuable information on the spatio-temporal characteristics of landslides in Java and their relationship with causative factors, thereby providing a sound basis for landslide investigation in more detail.
Coastal Evolution, Geomorphic Processes and Sedimentary Records in the Anthropocene Gomez, Christopher; Hart, Deirdre E.; Wassmer, Patrick; Kenta, Imai; Matsui, Hiroki; Shimizu, Mariko
Forum Geografi Vol 33, No 1 (2019): July 2019
Publisher : Universitas Muhammadiyah Surakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.23917/forgeo.v33i1.7551

Abstract

The question of whether or not we agree with the term Anthropocene becomes inconsequential when examining coastal environments. With few exceptions, anthropogenic encroachment on, and reshaping of, the global coastal zone is evident from space via multiple spectral views. Humans have become one of the dominant agents of coastal system change during the latest part of their relatively short existence, and nowhere is the humanization of coastal landscapes more evident than on islands. Using three island nations characterized by different stages and styles of coastal development ? New Zealand, Japan, and Indonesia - we investigate the role of anthropogenic activity in coastal evolution, geomorphology and sediment records. Using field investigations, Geographical Information System (GIS) analyses, and mathematical and conceptual models, we reveals how anthropogenic activity influences processes at multiple time and space scales, with enduring effects. Our first anthropogenic impact investigation focusses on the potential effects of sea level rise (SLR) due to anthropogenic climate change. Using the earthquake-induced land-subsidence experienced in Christchurch, New Zealand, as a relative SLR example (?Laboratory Christchurch?), evidence shows that coastal settlements are likely to be impacted not only at the shore but further inland via coast- connected waterways, where drainage is impeded due to an increase in the base level of that is the sea. Relative SLR makes it more difficult to evacuate water from subaerial and subsurface hydrosystems, and simulations show that future SLR is also likely to temporarily reduce some rivermouth sediment discharges, creating the potential for accelerated erosion in river-coast interface environments. In addition to flow-on effects from waterways, coastlines themselves have been highly affected by human activity over recent decades to centuries. In Tokyo, the shoreline has undergone artificial progradation, in places by more than 2 km, where concrete has supplanted mudflats, often at elevations above the hinterland of reclaimed areas. In addition to changes in Tokyo?s unconsolidated shores, consolidated coastal cliffs have been modified with the removal of natural talus buffers, again increasing the potential for erosion acceleration. Finally, in our third example, studies of the 2004 Indian Ocean tsunami and the 2011 Tohoku tsunami show that anthropogenic activities and structures play an important role in controlling the erosion and depostion of sediments during extreme events. A chronology of tsunami deposits from the Tohoku coast shows that sedimentary records from tsunami events have become thinner in recent centuries, independent of the incident tsunami wave hydrodynamics, and in relation to increasing levels of coastal plain, shoreline and nearshore development. In light of these multi-scale and multi-process effects, we argue that the Anthropocene is clearly distinguishable from the Holocene in coastal environments due to the significantly stronger signatures of human influence that characterise the former time period.
Spatial Distribution of Drifted-wood Hazard following the July 2017 Sediment-hazards in the Akatani river, Fukuoka Prefecture, Japan Shimizu, Mariko; Kanai, Sayaka; Hotta, Norifumi; Lissak, Candide; Gomez, Christopher
Forum Geografi Vol 34, No 2 (2020): December 2020
Publisher : Universitas Muhammadiyah Surakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.23917/forgeo.v34i2.12434

Abstract

In recent years, heavy rainfall leading to floods, landslides and debris-flow hazards have had increasing impacts on communities in Japan, because of climate change and structural immobilism in a changing and ageing society. Decreasing rural population lowers the human vulnerability in mountains, but hazards can still leave the mountain to the plains and sea, potentially carrying drifted-wood. The aim of the paper is to measure the distribution of wood-debris deposits created by the 2017 Asakura disaster and to rethink the distribution and spatial extension of associated disaster-risk zoning. For this purpose, the authors: (1) digitized and measured the distribution of drifted-wood, (2) statistically analyzed its distribution and (3) calculated the potential impact force of individual drifted timber as a minimal value. The results have shown that there is a shortening of the wood debris as they travel downstream and that the geomorphology has an important control over deposition zones. The result of momentum calculation for different stems’ length show spatially differentiated hazard-zones, which limit different disaster-risk potentials. From the present finding, we can state that we (1) need to develop separate strategies for sediments and wood debris (2) and for wood hazards, zonations can be generated depending on the location and the size of the deposited trees that differs spatially in a watershed.